The present invention relates to a sealing structure of an organic electro-luminescence light emitting element (organic EL element) that is used for an organic electro-luminescence display apparatus (organic EL display apparatus).
In the organic EL element, there is a possibility that a so-called dark spot (non light-emitting portion) may be generated, due to invasion of moisture into the element. Given this situation, the organic EL element is generally sealed by a sealing cap made of metal or glass, which is provided with a desiccant, thereby preventing the moisture from invading the element. As a technique for sealing the organic EL element by the sealing cap provided with the desiccant, there are known techniques as disclosed in the Japanese Patent Laid-open Publication No. H9-148066 (hereinafter, referred to as “patent document 1”), and in Japanese Patent Laid-open Publication No. 10-275679 (hereinafter, referred to as “patent document 2”).
According to the technique as disclosed in the patent document 1, the organic EL element is sealed by a sealing cap on the bottom of which there is fixed a desiccant to absorb moisture chemically, and the desiccant maintains its solid state even after absorbing the moisture. According to the technique as disclosed in the patent document 2, the organic EL element is sealed by a sealing cap having an absorbent porous layer, such as SiO2 and zeolite, formed on the internal surface.
In the meantime, for the purpose of reducing manufacturing cost and the like, there is known a technique as disclosed in the Japanese Patent Laid-open Publication No. 2002-280169 (hereinafter, referred to as “patent document 3”) in which the organic EL element is sealed without using the metal cap. According to this art as disclosed in the patent document 3, the organic EL element is sealed with a sealing board such that on one surface of the sealing board, double frame-like patterns (internal partition and external partition) are formed along the edge of the sealing board, by applying and burning a low-melting-point glass frit. Furthermore, a sealant is disposed between the internal partition and the external partition, and a moisture absorbent is applied on the region surrounded by the internal partition. Subsequently, the element substrate and the sealing board are bonded together, so that the organic EL element on the element substrate is placed inside the internal partition.